Hi,
I dont know how many of you had the idea how to save a machined part from beeing ruined.I come up with some idea that i will try it tomorrow(i have to open my electronics box of the mill).
Note: This post applies to those who use Gecko 320 servo drivers to drive their motors!
Here is the thing...
You machine a part with BIG! Gcode(Normally 3D machining).At 90 percent of the machined file, one servo faults by a reason(electronics do fail irrelevant of their quality etc).Normally the rest two axes continue to work, ruining the part
all you can do is to hit E-stop and have a face something like that>
Even if you realised fast the servo fault and be faster enough to hit the pause button and then re engage the servo,i dont think that you re faster than electricity!!!And the file may be 2 or 3 lines ahead from the position that the servo faulted.The contoller of DeskCNC doesnt know that there is a problem and continues to send commands to the drivers loosing the current position of the servo fault.I dont think that anyone can find the particular line when the servo faulted,and continue to machine the file from there!!!
The only solution to this problem is the one here:
G320 has an ERR/RES terminal.When a servo faults the red light comes up and this terminal goes to GND.You can make a wiring(the wiring diagram is inside the manual of the drive) to externally read the state of the drive by a LED and if you like to engage it or disengage it via a switch.The manual states that you can signal your controller that an error has occured and put the machine in E-stop.Thats the key to the solution.Instead of an E-stop (and consequentially a ruined part) you can wire up the ERR/RES terminal to PAUSE the machine!Solve the problem of the servo fault,if there is any and then UNPAUSE the machine to continue machining the file.Normally as i think it the Pause state will be instant(with some milliseconds delay) before the file moves to the next line or point.I know that your endmill might move some distance before the PAUSE, but If you have slow feed rate i think that this problem is minimized!That way the file stops executing together with servo fault.And you have all the time to correct the problem,engage back the servo and continue your work, by Unpausing the program!You have to wire the drives that way when ANY of the three drives fault the pause command will be send to controller.
To do that remember to activate the option "Enable external Pause" inside the machine setup of DeskCNC.
I think that this solution comes 90% close to success of saving your machined part.
PS:I will have to verify that the drive will continue to work from the same spot and go to the commanded one,even after all steps are zeroed because of the fault.
If you have any comments,welcome!!!
Panos